But many newbie users of the Resmed S9 are not shown how to access the LCD's efficacy data by the DME that sets up their machine.
So---if you are using a Resmed S9 Elite or a resmed S9 AutoSet and you want to know how to get to the LCD's efficacy data and what that efficacy data tells you about the quality of your therapy, this post should answer your questions.
Step-by-step instructions on how to get to the Sleep Quality Report on your S9's LCD
- Press the info button on the S9 to get into the Short Sleep Quality Report. You should see your Usage for the night, an icon indicating Mask Fit for the night, and the AHI for the night. Note that Mr. Red Frowny Face shows up if your excess leak rate is AT or ABOVE 24 L/min for at least 30% of the night. If you only see the Usage data, your DME has locked you out of the full Sleep Report Data. Take the machine back to theDME and demand that they change the setting for Sleep Quality from Usage to On. Or learn how to get into the clinical menu and set Sleep Quality to On yourself.
- If you want more detailed information, you can go from the short Sleep Quality Report to the more detailed Long Sleep Quality Report by holding both the info and the double check buttons down at the same time for three seconds or so. You may notice a brief flash.
- Use the large round knob to scroll down ONE icon on the left hand list of icons. You should now see the top of the detailed Sleep Quality menu. And then CLICK the round button to select the detailed Sleep Quality menu. This will now let you scroll all the way through the detailed Sleep Quality menu to see the AHI, AI, and CAI, which are at the bottom of this menu. It will also allow you to change the data period from 1 Day to 1 Week to 1 Month to 3 Months to get an idea of the averages of the data over longer time frames than over night.
Information on what data is available on the S9's LCD in the Long Sleep Quality Report
The S9's software detects four types of respiratory events: Obstructive apneas, central apneas, unknown apneas, and hypopneas. The unknown apneas are events that the S9's algorithm detects as apneas, but cannot tell whether the apnea is obstructive or central with enough certainty to classify them.
The AHI number is the Apnea/Hypopnea Index for the reporting period, which on the S9 LCD is typically the overnight number. For overnight (one day) data, the AHI is computed by the S9 as follows: It takes the number of all detectable events (obstructive apneas, central apneas, unknown apneas, and hypopneas detected) and divides that number by the time the machine was running. In other words, the AHI is the average number of apneas and hypopneas that occurred each hour the machine was on. The LCD display number on the S9 is simply truncated at one decimal place without any rounding as near as I can tell. I believe that for longer reporting periods (such as five days), ResScan simply averages the nightly AHI numbers to compute the one in the report. But I don't know for sure.
The AI number is the Apnea Index for the reporting period. It only counts the obstructive, central, and unknown apneas. In other words, the S9 computes this number by dividing the number of detected apneas (includes obstructive, central, and unknown apneas) by the time the machine was running. In other words, the AI is the average number of apneas that occurred each hour the machine was on. Again, the S9's LCD display number seems to simply be truncated at one decimal place instead of being rounded to one decimal place.
An example might help. Suppose that on a given night the S9 detects 15 total events---let's say there are 9 obstructive apneas, 2 central apneas, and 4 hypopneas---and that the machine was run for a total of 6.6 hours.
The S9's LCD's overnight AHI, AI, and CAI numbers are computed as follows:
AHI = 15/6.6 = 2.272727 = 2.2 (due to truncating the decimal)
AI = 11/6.6 = 1.666667 = 1.6 (due to truncating the decimal)
CAI = 2/6.6 = 0.303030 = 0.3 (due to truncating the decimal)
Let's suppose you look at the detailed Sleep Quality Data one morning and this is what you see:
Usage: 7.3The Usage number indicates you used the machine 7.3 hours overnight.
Pressure: 12.4
Leak: 9.6
AHI: 1.8
AI: 1.4
CAI: 0.3
The Pressure number is the 95% pressure level. For example, if the LCD says the Pressure = 12.4, that means that your pressure was AT or BELOW 12.4 cmH2O for 95% of the night. It also means that your pressure was AT or ABOVE 12.4 cmH2O for 5% of the night. Note: If you are using an S9 Elite or if you are using an S9 AutoSet in CPAP mode, the Pressure number will just be your Pressure setting and it will remain the same every day.
The Leak number is the 95% excess leak rate in Liters per minute (L/min). Since the LCD says the Leak = 9.6, that means that your unintentional leak rate was AT or BELOW 9.6 L/min for 95% of the night. It also means that your unintentional leak rate was AT or ABOVE 9.6 L/min for 5% of the night.
And how long is 5% of the night? Well, 5% of one hour = 3 minutes. So you can multiply the Usage time by 3 minutes to get an idea of how long your leaks were above the reported leak rate: In our example, leaks were ABOVE 9.6 L/min for a total of no more than 7.3 * 3 = 21.9 minutes and the Pressure was above 12.4 for a total of no more than 7.3 * 3 - 21.9 minutes.
Since the usage was about 7.3 hours, we can also estimate the number of events you had and what type they were from the LCD's AHI, AI and CAI numbers as follows:
Total number of apneas and hypopneas:
AHI x Usage = (1.8 events per hour) x (7.3 hours) = approx. 13.14 events = 14 events (round UP since there's a fraction)
Total number of apneas (all types):
AI x Usage = (1.4 apneas per hour) x (7.3 hours) = approx. 10.22 apneas = 11 apneas (round UP since there's a fraction)
Total number of central apneas:
CAI x Usage = (0.3 CAs per hour) x (7.3 hours) = aprox. 2.19 central apneas = 3 central apneas (round UP since there's a fraction)
Estimated Total number of obstructive apneas:
First, an estimate of the OAI is simply OAI = AI - CAI. Note that if your S9 detects any Apneas of Unknown type, that will throw this calculation off, but it's still a good estimate. So here we go:
OAI = AI - CAI = 1.4 - 0.3 = 1.1 and
OAI x Usage = (1.1 OAs per hour) x (7.3 hours) = 8.03 obstructive apneas = 8 apneas (since we truncate to one decimal and because 8 + 3 = 11 apneas)
Total number of hypopneas:
First, an estimate of the HI is simply HI = AHI - AI. So here we go:
HI = AHI - AI = 1.8 - 1.4 = 0.4
HI x Usage = (0.4 Hypopneas per hour) x (7.3 hours) = 2.93 hypopneas = 3 hypopneas (Which make since because 11 apneas + 3 hypopneas = 14 events.)
Of course, to get more detailed information about when the events happened and how long each of the apneas lasted, you will need to download the data into ResScan (or Sleepy Head) and look at the graphs for the night.
To improve your health from sleep apnea, get resmed s9 sleep therapy equipment online.
ReplyDeleteNOTE TO READERS: The link in Alisha Johnson's reply is to a Resmed ESCAPE which is a BRICK that records NO useful data.
ReplyDeleteResmed s9 Escape features user-friendly technology to enhance your breathing comfort and reduce system noise
ReplyDeleteConcerning Amit Kumar's comment: While the Resmed S9 Escape does have the same "user-friendly" EPR system and "easy breathe" technology, the S9 Escape remains a BRICK that records NO useful data. With an S9 Escape and with the S9 Auto Escape, the user gets NO feedback concerning LEAK data. You need the leak data in order to troubleshoot any problems you might have with leaks. Contrary to what we might think, leaks (even LARGE leaks) do not always wake us up. But long LARGE leaks can have seriously and adversely affect the efficacy of CPAP therapy. Insurance companies and Medicare typically pay for CPAP machines by HCPC (the HCPC code for *any* CPAP machine is E0601). Because of this fact, many DMEs work very hard to persuade new PAPers to accept an S9 Escape instead of a full efficacy data machine like the S9 Elite or the S9 AutoSet for one simple reason: The DME makes more money by selling you the BRICK than they do by selling you a FULL efficacy data machine. But the problem with a BRICK like the S9 Escape is simply this: If (when) you run into problems making this crazy therapy work in your own bed, there is NO data for anyone---the sleep doc, the DME, and you---that can help you figure out what is going wrong. And any suggestions the sleep doc or the DME makes for altering your therapy are shots in the dark. Sleep docs and DME will commonly suggest using a chin strap on the grounds that "you must be leaking", which won't fix a damn thing if your problems are NOT related to leaks. Increasing the pressure is another common "blind" suggestion by docs and DMEs dealing with a patient who is not getting better with CPAP therapy. While that's an appropriate suggestion if the residual AHI is too high AND the events are obstructive, it's a highly inappropriate suggestion if the problem is that the patient is in the 10% or so of PAPers who develop Complex Sleep Apnea once they start therapy. Such folks are often unlucky enough to have docs and DMEs make blind suggestions for months and months and months before somebody finally decides that maybe a trip back to the lab is in order. With a full efficacy data machine, the problem with emergent CAs would show up in the data as soon as the problem starts and it can then be addressed much, much sooner with an appropriate strategy.
ReplyDeleteThanks for the great info, what leak rates are acceptable.
ReplyDeleteOn a Resmed S9, the leak rate that is reported is the excess leak rate. And according to Resmed engineers, a Large Leak is defined to be anything over 24 L/min. So you want to try to keep the leaks under 24 L/min. A short lived Large Leak now and then shouldn't affect your therapy or the data too much, but prolonged leaks at or above 24 L/min can cause serious problems with both. Mr. Red Frowny Face shows up in the short Sleep Quality Report in the morning if the leak rate is AT or ABOVE 24 L/min for at least 30% of the night. That's when you know for sure that your leaks really are seriously bad and must be dealt with.
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